Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, generator, gearbox, nacelle, and one or more rotor blades. The rotor blades capture kinetic energy from wind using known airfoil principles and transmit the kinetic energy through rotational energy to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
To ensure that wind power remains a viable energy source, efforts have been made to increase energy outputs by modifying the size and capacity of wind turbines. One such modification has been to increase the length of the rotor blades. However, as is generally understood, the loading on a rotor blade is a function of blade length, along with wind speed and turbine operating states. Thus, longer rotor blades may be subject to increased loading, particularly when a wind turbine is operating in high-speed wind conditions.
During the operation of a wind turbine, the loads acting on a rotor blade are transmitted through the blade and into the blade root. Thereafter, the loads are transmitted through a pitch bearing disposed at the interface between the rotor blade and the wind turbine hub. As a result, the pitch bearings are often subjected to extreme, varying and/or opposing loads. For example, the pitch bearing experiences a large, dynamic bending load due to a gravity load vector that reverses with each revolution of the rotor. When such a large, dynamic bending load is combined with the continuous pitch adjustments made to the rotor blade during each revolution of the rotor, sections of the roller elements contained within the bearing tend to migrate towards one another, thereby generating a high circumferential compressive load between the roller elements. Such compressive loads can lead to damage to one or more of the pitch bearing components.
Accordingly, a sensor assembly and a related system and method that allow compressive loads between adjacent roller elements of a wind turbine bearing to be monitored would be welcomed in technology.